New York University professor William Easterly spent 16 years as a research economist for the World Bank. He points out that, from 1960 to 2003, the world spent $568 billion (in 2005 dollars) to end poverty in Africa. "Yet, these efforts," he writes, "still did not lift Africa from misery and stagnation."

Instead of funding what Easterly calls "big plans," such as those outlined in the UN's Millennium Development Goals, he argues that donor nations should focus on "piecemeal solutions" — smaller projects that are easier to plan, run, monitor, and evaluate and more likely to deliver results. He singles out many successful examples in the area of global health.

Proponents of aid counter that the lack of success shouldn't be surprising. The percentage of GNP the U.S. now commits to international aid is far less than what America spent to resuscitate Europe after World War II. Further, they say, rich countries haven't provided aid that is predictable, long-term, well-coordinated, and sufficient enough to bring about real change.